Method of and apparatus for die rolling



Feb. 23, 1937. T. N. SLOAN 2,071,856

METHOD OF AND APPARATUS FOR DIE ROLLING Filed May 4, 1954 5 Sheets-Sheet1 Snventor Cittorneg Feb. 23, 1937. T. N. SLOAN 2,071,866

METHOD OF AND APPARATUS FOR DIE ROLLING Filed May 4, 1954 s Sheets-Sheet2 Patented Feb. 23, 1937 UNITED STATES PATENT OFFICE IVIETHOD OF ANDAPPARATUS FOR DIE ROLLING Application May 4, 1934, Serial No. 723,819

9 Claims.

This invention relates broadly to the shaping and forming of metal andmore particularly to an improved method of and apparatus for die rollingforging blanks and the like from ferrous metals, the blanks havingaccurately spaced portions of different cross sectional areas, withoutthe formation of a fin or flash on the rolled article.

In my co-pending United States patent application, Serial No. 560,299,filed August 31, 1931, now patent No. 1,998,970, I have fully disclosedand claimed an improved flash-free die rolled forging blank and a methodof and apparatus for manufacturing same. The leader bar is die rolled toform a plurality of connected, flash-free blanks with large and smallsections accurately spaced apart the desired distances, and withreductions ranging up to about 40% in medium sized sections such asabout 1 x2". With larger sections the reduction attainable is somewhatgreater.

According to the present invention I have die rolled a leader bar intostrings of connected flash-free, forging blanks, each blank havingsubstantially straight or plane sides and irregular top and bottomsurfaces, and having large and small sections accurately spaced apartdesired distances, and with reductions of up to about 63% in mediumsized sections without formation of flash. Where I-beam sections and thelike are desired for a part of the length of the blank, I have, by thepresent invention, obtained reductions as great as 63% from the largestto the smallest section in the blank without flash and while obtainingthe desired spacing between large and small sections.

Also, by the present invention, I have provided rolls in each of whichthe grooves are defined by a bottom wall and one side wall, after thefashion of a rabbeted recess or groove, and have thereby not onlyovercome any tendency of the blank to stick in the groove but have alsoobviated largely, if not completely, the use of end thrust bearings.Moreover, since the portions of the rolls which define the sides of thegroove overlap each other and extend beyond the bottom of each groove,these portions constitute flanges which serve as side guides for theleader bar. These flanges project far enough ahead of the verticalcenter line of the rolls to prevent lateral flow of the leader bar metalwhich, in prior devices, could occur and often did occur with resultantformation of flash or damage to the rolls or both.

Other objects of my invention will appear from the following descriptionof my improved method,

one form of rolls adapted to carry out my method, and several types offorging blanks which may be rolled by my method and apparatus, referencebeing had to the accompanying drawings, in which- Figure 1 is a sideelevation of a pair of die rolls of my improved form.

Figure 2 is an end view of the roll shown in Figure 1.

Figure 3 is a vertical cross section taken on line 3-3 of Figure 1,showing a leader bar, partly in section, between the rolls.

,Figure 4 is a plan view of the pair of rolls shown in Figure 1, alsoillustrating the leader bar entering the rolls and the finished articleleaving the rolls, and having a portion of the top roll cut away tobetter illustrate the engagement of the rolls with the stock.

Figure 5 is a perspective view of a portion of a string of automobilefront axle forging blanks which have been rolled by the rolls of Figure1.

Figure 6 is an enlarged vertical cross section taken on a plane joiningthe axes of the rolls and illustrating the portion of the roll passadapted to form the portion of the blank indicated by line 6--6 ofFigure'5.

Figure 7 is a view similar to Figure 6 but illustrating the roll passwhich forms the portion of the blank indicated on line '|-l of Figure 5.

Figure 8 is a view similar to Figures 6 and 7 but illustrating theportion of the roll pass which forms the section of the blank indicatedat line 8-8 in Figure 5.

Figures 9 and 10 are plan and side elevational views respectively of aform of crank shaft forging blank which is adapted to be rolled by myimproved method and apparatus.

Figures 11, 12, 13, 14 and 15 are cross sectional views of the blankshown in Figures 9 and 10 taken on lines ll- -H, I2--l2, I3l3, i4l4 andI5-l5 respectively of Figure 10.

Figures 16 and 17 are plan and side elevational views of another form ofcrank shaft forging blank which may be rolled by my method and with myapparatus.

Figures 18, 19, 20 and 21 are cross sectional views taken on lineslB-IB, l9--I9, 20-20, and 2|2I of Figure 17.

Figure 22 is a cross sectional view illustrating a type of leader barwhich may be advantageously used with my rolls.

Referring now to Figure 1, which illustrates rolls adapted to roll theblank of Figure 5, the upper roll A is carried by a suitable shaft l andthe lower roll 13 is carried on its corresponding shaft 2. The rollshafts are, of course, mounted in bearings (not shown) in the usualmanner and may be connected to any suitable driving means (also notshown) so that they will rotate together to maintain the proper angularrelation between the different portions of the rolls. Five formingpasses are provided between rolls A and B but it will be understood thatthis number may be increased or diminished without departing from thespirit of my invention. The upper roll A includes the matrix faceportions 5, 6, I, 8 and 9, the outwardly extending flange portions III,II and i2, and the flange grooves I3, I 4 and I5. In like manner thelower roll B comprises the matrix faces l6, I1, I 8, I9 and 20, theoutwardly extending flanges 2|, 22 and 23, and the flange grooves 24, 25and 26.

The rolls are so disposed relative to each other that the flanges 23, 22and 2| of roll B extend respectively into the flange grooves l5, l4 andI8 of roll A, while flanges IO, N and I2 of roll A extend respectivelyinto flange grooves 26, 25 and 24 of roll B.

As will be more fully described later, the grooves in the rolls are madejust wide enough to provide a very slight clearance for the flanges andit will be seen that with this roll arrangement, considering for examplethe left hand roll pass 21 (Figure l), the top surface and left handside of the roll pass are defined by the matrix face 9 and flange l2 ofroll A while the bottom surface and right hand side of the groove aredefined by the matrix face l6 and the flange 2| of the roll 13. Incorresponding manner each of the four other roll passes are formed withthe top and one side surface in the top roll and the bottom and otherside surface in the bottom roll. With this arrangement the side surfacesof the finished blanks'have little or no tendency to stick to either thetop or bottom rolls because,. as the blanks leave the rolls, the sidesurfaces of the flanges M, II and I2 of the upper roll A are movingupwardly while the side surfaces of the flanges 2|, 22 and 23 of thelower roll B are moving downwardly.

The particular rolls illustrated in Figures 1, 2, 3, 4, 6, '7 and 8 aredesigned for rolling a string of connected but severable front axleforging blanks from a leader bar: Of course, by varying the contour ofthe matrix faces of the rolls and the flanges any desired article ofthis class may be formed. Other types of articles which can be rolledare the crank shaft forging blanks illustrated in Figures 9 to 21.Referring to Figure 5, which illustrates a portion of a string of rolledblanks, it will be noted that the dimension :2 of the string of blanks,that is, the horizontal dimension of the string of blanks, is constantthroughout the blank while the other dimensions vary a great deal atdifferent points of the blank. The end portions 28 of the blank have across sectional area preferably but slightly smaller than the crosssection of the leader bar which is fed into the rolls. Spring bossportions 28 of the axle blanks are somewhat smaller in cross sectionthan the portions 28. Intermediate the portions 28 and 29 are sections30 of reduced cross sectionalarea while the relatively long r-beamsection 3| which extends btwen the sections 28 is of greatly reducedcross sectional area as compared with sections 28 and 29.

Referring now to Figure 3, the matrix faces of the rolls are cut so thata single revolution of the rolls will form one complete axle blank. Theportions a of the rolls are adapted to form the ends 28 of the axleblank. The portions 12 form the reduced sections 30, portions 0 of therolls form the spring bosses 29 while the portions d of the rolls formthe I-beam center section 3| of the axle.

Of course, if it is desired to roll a string of forging blanks forforming connecting rods, crank shafts or other die rolled articles thematrix faces of the rolls will be formed with the proper contours. Insome instances it may be preferable to form the rolls so that a singlerevolution will form more than one article. In rolling the crank shaftblanks of Figures 9 to 21 the matrix face of the top roll will of coursebe different from the matrix face of the bottom roll as the blanks arenot symmetrical about the longitudinal axis of the blank.

As the forming passes between the rolls are substantially completelyclosed, the clearance between the flanges of one roll and the grooves ofthe co-acting roll being very small, preferably about .003" in theillustrated rolls, the formation of flash is positively prevented. Ihave found that a small clearance such as noted above will not permitthe metal to be forced into the space between the side of a flange andthe side of its groove at the temperature commonly used for rollingarticles of this kind from fe rous metals. However, if the leader bar isrolled a relatively high temperature greater clearance may be usedwithout the formation of flash than can be used when the leader bars arerolled at a relatively low temperature, for the lower the temperature ofthe bar the greater is the tendency to formation of flash.

Another factor which enters into the formation of flash is thepercentage of reduction in cross sectional area which is effected by therolls. The greater the percentage of reduction the greater the pressuretending to force the metal into any clearance space between the rolls.Thus, where large reductions in areas are to be made it is be kept verysmall and my roll arrangement greatly facilitates the use of such smallclearance.

In Figure 22 I have illustrated the general cross sectional shape of aleader bar which may be advantageously used with my improved die rolls.'By properly relieving the diagonally opposite corners 40 and 4| of theleader bar the tendency toward the formation of flash or fln is reduced.The leader bar enters the rolls (for example the left hand pass ofFigure 6) with the relieved comer 40 entering the upper right handcorner of the pass and the relieved corner 4| entering the lower lefthand corner of the pass. Of course the exact shape of the leader bar maybe varied for rolling different articles and Figure '22 is intendedmerely to illustrate how the opposite corners of the bar may be relievedto relieve the flash forming pressure at the clearance spaces betweenthe rolls while still providing proper filling of the roll pass. In dierolling with the next pass to the right from the left hand pass of therolls of Figure 6, the corners 42 and 43 of the leader bar would berelieved or chamfered and the corners 48 and 4| would be left full.

It has been observed that in the die rolling of forging blanks from aheated leader bar, the metal of the bar spreads laterally orhorizontally when large vertical reductions of the bar are being made.If any vertical piling up occurs, it can be handled by the rolls withoutinjury to the latter, but the metal which has spread laterally maycontact with the edges of the matrix grooves and rolls and causedetrimental wear thereof. By making the outwardly projecting flanges ofthe rolls of a diameter sufficiently large to form guides for the sidesof the leader bar for the space within which exists this tendency tolateral spread of the leader bar as it enters the matrix grooves, thedifficulty incident to lateral spread is eliminated and the metal isconfined laterally between substantially straight parallel planes.

In designing my rolls I proportion the flanges H), II, II, 2|, 22 and 23so that lateral spread of the metal of the leader bar ahead of the rollswill be prevented and a guide restricting lateral flow will be providedfor a distance at least as far ahead of the center line of the rolls asthere exists any tendency for the metal to spread laterally. Thisfeature of my invention is of particular importance as it prevents theformation of flash, excessive wear on the relatively sharp edges of theroll, greatly lengthens roll life, and permits greater reduction of thebar than would otherwise be possible.

I am aware that prior to my invention it has been proposed to utilizerolls having matrix surfaces and outwardly projecting flanges in therolling of irregularly shaped articles. In United States Patent No.55,270 to Fowler such an arrangement of rolls is illustrated. However,in Fowlers rolls and in others of this type with which I am familiar theend thrust on the rolls and roll shafts, which is necessarily great withsuch a roll arrangement, must be taken up by thrust bearings or thelike. With my roll arrangement, however, I provide a plurality of rollpasses and flanges whereby the side thrusts on one roll, which is set upby the passage of the metal through one pass, is opposed by severalflanges. This arrangement is of particular importance in my constructionin which I provide small clearances between the outwardly projectingflanges of the rolls and their corresponding grooves in the oppositerolls. Where end thrust is transmitted from one roll to another throughsuch outwardly extending flanges the wear due to the friction isdistributed over the several flanges and groove walls and thisarrangement is. very effective in minimizing such wear and helpful inmaintaining the clearance which I desire.

With my improved roll, illustrated in the drawings, the metal iscompletely supported and guided on the sides of the leader bar beforethe rolling pressure is applied to the top and bottom of the bar. Thismakes possible extremely great reductions in cross sectional area, ithaving been found in actual practice that reductions from the leader baras great as 63% may be rolled satisfactorily and without the formationof fln while maintaining the requisite accuracy of spacing of therelatively large and small portions of the blanks. The greater thepercentage of reduction in the roll pass the greater appears to be thetendency for the metal to back up ahead of the rolls and to spreadlaterally. Therefore, with my rolls, in making such large reductions theflanges of the rolls will be designed to form restraining side walls fora distance far enough ahead of the vertical center line of the rolls toprevent the leader bar from spreading laterally.

By correlating the clearance spaces between the roll flanges and grooveswith the temperature of the metal being rolled and the percentage ofreduction of cross sectional area effected by the rolls as abovedescribed I am able to die roll, without flash, forging blanks havingextremely high reductions and having relatively large and small portionssubstantially accurate as to size and spacing. So far as I am aware suchblanks have not been successfully die rolled prior to my invention.Restraining the metal from lateral flow ahead of the rolls for adistance as far as any tendency for such flow exists relieves the edgesof the matrix grooves and flanges from the excessive wear which occurswith other types of rolls.

Although I have illustrated and described only one form of roll andseveral articles which can be formed .by my improved rolls and method,it will be understood that variations and modifications may be made inthe type of roll used, both to accommodate the manufacture of differentarticles and 'to meet other conditions which may arise, and also myprocess may be modified without departing from the spirit of myinvention. I do not, therefore, wish to be limited strictly to thespecific embodiments of my invention herein illustrated and describedbut claim as my invention all forms thereof coming within the scope ofthe appended claims.

I claim:

1. In die rolling apparatus, a pair of rotatable die rolls, each rollhaving a matrix face extending in a direction generally parallel to theroll axis, a plurality of spaced flanges extending radially outwardlyfrom said matrix face, a plurality of grooves extending radiallyinwardly from said matrix face, said grooves being disposed one betweeneach adjacent pair of said flanges, the flanges of each roll extendinginto the grooves of the other roll and dividing the matrix faces wherebya plurality of roll passes are provided, each pass having its top andone side surface formed in one roll and its other surfaces in the otherroll and having the engaging portions of the rolls disposed on oppositesides of the pitch line of the rolls.

2. In apparatus of the type described, a top roll having spaced matrixfaces, a flange extending radially outwardly between said matrix faces,said roll having grooves on the opposite sides of said matrix faces fromsaid flange, a bottom roll having spaced matrix faces, grooves betweensaid bottom roll matrix faces and flanges extending radially outwardlyfrom the sides of said bottom roll matrix faces opposite grooves in saidtop rool, and means for rotatably supporting said top and bottom rollswith their matrix faces opposite and the flanges of the top rollextending into the grooves of the bottom roll and the flanges of thebottom roll extending into the grooves of the top roll.

3. In apparatus of the type described, a top roll having spaced matrixfaces, a flange extending radially outwardly between said matrix faces,said roll having grooves on the opposite sides of said matrix faces fromsaid flange, a bottom roll having spaced matrix faces, a groove betweensaid bottom roll matrix faces and flanges extending radially outwardlyfrom the sides of said bottom roll matrix faces opposite said grooves insaid top roll, and means for rotatably supporting said top and bottomrolls with their matrix faces opposite and the flange of the top rollextending into the groove of the bottom roll and the flanges of thebottom roll extending into the grooves of the top roll whereby a pair ofdie rolling passes will be formed, each pass having its top and one sidesurface defined by the top roll and its bottom and other side surfacedefined by the bottom roll.

4. The method of forming a string of substantially identical,irregularly shaped, forging blanks which includes the steps of passing aheated leader bar of substantially uniform cross-section axially betweena pair of die rolls and, while so doing, reducing the verticaldimensions of the bar by varying amounts to form portions of large andsmall cross-sections with coincident tendency of the metal to spreadlaterally, and confining the sides of the bar throughout the distancewherein said tendency exists, thereby preventing such lateral spread.

5. The method of forming -a string of substantially identical,irregularly shaped, forging blanks which includes the steps of passing aheated metal leader bar of substantially uniform crosssection axiallybetween a pair of die rolls, and,

while so doing, reducing the vertical dimensions of the bar by varyingamounts to form portions of large and small cross-sections withcoincident tendency of the metal to'spread laterally, and

confining the sides of the bar between substantially straight parallelplanes throughout the distance wherein said tendency exists.

6. The method of forming an irregularly shaped forging blank whichincludes the steps of passing a heated metal bar of substantiallyuniform cross-section axially between a pair of die I rolls and, whiledoing so, reducing the vertical wardly from the matrix face of eachroll, the groove of each roll being disposed opposite the flange of theother roll and the flange of each roll extending into the groove of theother roll whereby a roll pass is provided having its top and one sidesurface formed in one roll and its other surfaces in the other roll andhaving the engaging portions of the rolls dispoud on opposite sides ofthe pitch line of the rolls.

8. The method of forming a string of substantially identical, irregularshaped, forging blanks which includes the steps of passing a heatedleader bar of substantially uniform cross-section and diagonallyopposite rounded corners axially between a pair of die mils and, whileso doing, reducing the vertical dimensions of the bar by varying amountsto form portions of large and small cross-sections with coincidenttendency of the metal to spread laterally, and confining the by varyingamounts up to about 63% to form por- 1 tions of large and smallcross-sections with coincident tendency of the metal to spreadlaterally, and confining the sides of the bar throughout the distancewherein said tendency exists, thereby preventing such lateral spread andthe formation of fins or flash at the initially rounded comers of thebar.

THOMAS N. SLOAN.

